first off i didnt know there was any rules to this forum i thought this was a place where if people need help they came here to ask for it not to be treated like Sh**!!
When you signed up for this forum, two days ago, you were given a link to the forum rules, and you said you read and agreed to them. There's also a link to them, in red, at the top of every single page in this forum. That you ignored them is on you.
The rules aren't there so we can point and laugh at n00bs; they're there to help us help you. None of us are paid to be here; we're here because we want to help out. Providing the information required by the rules makes it much more likely that you'll get a response at all, and that you'll get a useful response faster. Providing accurate and complete information about what you've done to this point does the same. When you post that you've run 'smartctl -a /dev/ada0', we have no way of knowing that you actually ran it on /dev/ada1--we're just left wondering why you ran that command, and gave that output, on a disk that wasn't reporting errors. When you post that you ran 'zpool status Main-Server', we have no way of knowing you actually ran 'zpool status Unixnet'.
Now, to your actual issue. As I wrote previously, and
@rogerh more recently, ada1 is failing, hard. It needs to be replaced immediately, following the instructions in the manual (that link is also at the top of the page). Note that the smartctl output gives its serial number (which you've deleted here for whatever reason). When you remove it, verify that the serial number on the label matches the one in the smartctl output from that drive. Replace it and let it resilver, and you should be fine. ada3 is showing some questionable SMART data, but I don't think it warrants replacing immediately.
I agree with
@rogerh that you almost certainly replaced the wrong drive. The SMART output of ada2 shows only 148 power-on hours, while ada1 and ada3 show 16000-19000 hours, and ada0 shows 1400.
Once you've taken care of ada1, set up a sensible schedule of SMART tests on your drives. Right now it looks like you're running hourly short tests, and apparently no long tests. A more common and useful schedule would be to have a short test every day, few days, or week, and a long test every 1-4 weeks. You can set these up through the web GUI, and again, the process is described in the manual.